1. Field of the Invention
This invention relates to tamper proof locks and fittings and more particularly, to tamper proof service bolts which are designed to be used in such tamper sensitive closure services as sealing railroad switches, gas and electric meters and the like, as well as railroad boxcars, automobile hoods, gates and doors, in non-exclusive particular. In a first preferred embodiment, special head service bolts are provided, each of which includes a base member having a head on one end, a collar of selected shape fitted over the opposite end of the base member and a connecting bolt extending through the cylindrical collar and threadably seated in the base member for securing the cylindrical collar to the base member. A specially designed head recess provided in each connecting bolt requires a corresponding specially designed tool to remove the connecting bolt and the collar from the base member. In a second preferred embodiment of the invention retainer clip service bolts are provided, wherein each collar is attached to a corresponding base member by means of a retainer clip, such that removal of the collar from the base member cannot be effected without destroying the retainer clip service bolts. A sacrifice head service bolt is also provided where the collar is fitted on the base member and a sacrifice head having a thin, frangible neck is threaded on the base member, the bottom element of the sacrifice head being countersunk in the collar when the top element of the sacrifice head is stripped from the bottom element at the frangible neck. In another preferred embodiment of the invention a cross-thread nipple service bolt is provided, wherein a threaded nipple extends from one end of the base member and a cross-thread collar having an internally threaded seat is designed to receive the threaded nipple, such that the threaded nipple irreversibly cross-threads in the dissimilarly-threaded cross-thread seat, upon rotation of the cross-thread collar with respect to the base member. Like the retainer clip service bolts, removal of the cross-thread collar from the base member cannnot be effected without cutting the base member or collar or otherwise destroying the cross-thread nipple service bolt.
Security of various enclosures and tamper proof service bolt applications, including closures for warehouses, railroad boxcars, fences and even the engine compartments of automobiles and gas and electric meters, in non-exclusive particular, has become an ever increasing problem. Conventional locks such as padlocks and the like are of limited value in many instances, because of the variety of keys which must sometimes be distributed to various employees and others to gain entrance to the enclosures. Furthermore, padlocks are also easily cut with bolt cutters and other tools and therefore offer limited protection to the enclosure contents. Moreover, certain security applications, such as gas and electric meters require special closures which must be destroyed to provide the necessary access.
Accordingly, it is an object of this invention to provide tamper proof service bolts for application to the gate or door of an enclosure, or on a switch or the like, to prevent the unauthorized entry into the enclosure or operation of the switch.
Another object of this invention is to provide special head service bolts which are each characterized by a base member having a head on one end, a collar which fits over the opposite end of the base member and a connecting bolt designed to engage the collar and threadably engage the base member, which connecting bolt is fitted with a special head recess requiring a corresponding tool for engagement and removal.
Another object of the invention is to provide retainer clip service bolts for securing a closure or the like, which service bolts include a circumferential groove located on a base member having a head on one end, a corresponding groove provided inside a longitudinal bore in the collar and a retainer clip initially fitted to the base member and seated in the corresponding groove located in the collar when the base member is inserted in the collar, to permanently secure the base member to the collar. Removal of the retainer clip service bolt from the closure application requires destruction of the base member or collar.
Still another object of this invention is to provide a sacrifice head service bolt device for securing a closure, switch or the like, which device is characterized by a base member fitted with a head at one end and a threaded nipple on the opposite end, a collar fitted over the threaded nipple and the base member and a sacrifice head threaded onto the threaded nipple, wherein the grip segment of the sacrifice head may be twisted from the threadably secure portion of the sacrifice head to prevent removal of the recessed collar from the base member. Removal of the retainer clip service bolt from the closure requires destruction of the base member or the collar.
A still further object of this invention is to provide an aluminum cross-thread nipple service bolt having a base member provided with a head on one end and a threaded nipple on the opposite end for insertion in a cooperating, dissimilarly-threaded nipple seat located in a cross-thread collar, wherein the threaded nipple is cross-threaded in the cross-thread collar by rotating the collar with respect to the base member. Removal of the cross-thread nipple service bolt from a closure also requires destruction of either the base member or the collar.
2. Summary of the Invention
These and other objects of the invention are provided in tamper proof service bolts which are designed for engagement with the closure fittings or brackets of an enclosure, railroad switch, gas and electric motor or the like, which service bolts either require a special tool for removing a connecting bolt element and separating the collar and base member elements, or destruction of the base member or collar elements to remove the service bolts from the respective fittings.